电感调谐无栅间隙双重入同轴谐振腔TM310模的研究

本文对无栅间隙双重入圆柱型同轴谐振腔的TM310模的场分布进行了研究。对无栅间隙双重入同轴腔中TM310模的场分布进行理论分析,得到最佳注波互作用的漂移管设置方式和高阶模TM310模场分布稳定的同轴腔结构,同时分析了电感调谐膜片影响TM310模场分布均匀性的原因。并利用三维电磁场软件对一个电感调谐同轴腔进行了数值模拟,研究了调谐膜片与外腔壁距离变化时,谐振腔内TM310模场分布的变化规律,得到了调谐膜片离原腔壁越近,场分布越均匀的结论。     

电感调谐无栅间隙双重人同轴谐振腔TM310模的研究

本文对无栅间隙双重入圆柱型同轴谐振腔的TM310模的场分布进行了研究。对无栅间隙双重入同轴腔中TM310模的场分布进行理论分析,得到最佳注波互作用的漂移管设置方式和高阶模TM310模场分布稳定的同轴腔结构,同时分析了电感调谐膜片影响TM310模场分布均匀性的原因。并利用三维电磁场软件对一个电感调谐同轴腔进行了数值模拟,研究了调谐膜片与外腔壁距离变化时,谐振腔内TM310模场分布的变化规律,得到了调谐膜片离原腔壁越近,场分布越均匀的结论。     

多注速调管TM310模同轴谐振腔杂模抑制的研究

针对工作在TM310模的同轴谐振腔提出了一种通过在腔中设置重入式金属环来增大工作模式与邻近杂模频率间隔,进而实现杂模抑制的方法。通过等效电路法研究了金属环设置前后工作模式及其邻近模式频率变化的规律,发现通过适当地设置金属环可以获得较大的频率间隔。借助仿真软件CST-MWS验证了该法的有效性,并分析了金属环的各尺寸参数对模式频率及频率间隔的影响,以及金属环的设置对工作模式电场的影响。优化选取了适当的金属环参数,使某X波段多注速调管同轴谐振腔中工作模式与邻近杂模的最小频率间隔达到1.2 GHz。     

TEM模式同轴谐振腔低气压放电蒙特卡罗仿真和实验研究

随着无线通信系统高频小型化的发展趋势,对微波滤波器设计提出更为严苛的要求。其中功率容量作为衡量滤波器性能的重要指标,在滤波器尺寸不断缩小的情形下面临严峻的挑战。谐振器作为滤波器基本组成单元,对单一谐振器的功率容量准确预测十分重要。本文针对工作频率在2.6 GHz的TEM模式同轴谐振器,将电容加载的耦合结构近似为平行平板结构,利用单粒子蒙特卡罗方法仿真获得同轴谐振器临界击穿电场,实现了对该结构同轴谐振腔的低气压放电功率阈值仿真预测。对所设计同轴谐振腔开展低气压放电实验研究,获得了100～1000 Pa气压范围内击穿功率阈值随气压的变化关系实验曲线,并验证了单粒子蒙特卡罗仿真预测方法的准确性。     

速调管双耦合口输出回路间隙阻抗频率特性的计算

采用等效电路理论,建立了双耦合口输出腔间隙阻抗频率特性的冷测模拟计算方法。运用该方法,并借助CST-MWS三维电磁场计算软件,计算分析了某S波段单间隙双耦合口输出腔的间隙阻抗频率特性。结果显示,本方法与采用场分析法及散射曲线法得到的结果符合良好。     

W波段TE6,2模同轴开放式谐振腔的研究与设计

详细研究了一种用于回旋管冷测的三段式同轴谐振腔模式激励器,该模式激励器利用同轴开放腔的选频选模特性将输入的W波段的波功率转换为TE6,2模式输出。基于缓变截面波导理论,研究了同轴谐振腔激励TE6,2模式的机理;求解了同轴波导中TE模式的特征根和不均匀弦方程并得到腔体谐振频率及Q值;分析了同轴腔内外半径对谐振频率的影响;给出了W波段高纯度TE6,2模谐振腔优化设计的参数;并用电磁仿真软件对其进行仿真计算,结果表明:该谐振腔的TE6,2模式纯度达到99.51%。     

毫米波准光高阶模式激励器的研究与设计

基于毫米波准光模式传输和变换理论,详细研究了准光模式激励器通过波纹喇叭天线、准抛物柱面反射器和同轴开放式谐振腔激励圆极化高阶目标模式的原理。分析了W波段波纹喇叭天线产生准高斯模式HE11的过程;利用几何射线法研究了准抛物反射面天线作为腔体辐射馈源的设计方法;通过小孔耦合理论研究了侧壁开孔的三段式同轴谐振腔激励高阶模式的机理。同时,该文还优化设计了工作模式为TE62模,工作中心频率为94.8 GHz的准光模式激励器,使用三维电磁仿真软件FEKO仿真计算结果表明该模式激励器在94~96 GHz频率范围内目标模式的纯度超过95%,系统效率达到34%。     

三间隙耦合输出回路间隙阻抗频率特性的测量

从多端口微波网络等效的角度,讨论多间隙耦合输出回路间隙阻抗频率特性的测试问题,并以X波段三间隙耦合输出回路为例,分别从模拟测量和实际测量两个方面确定了其间隙耦合阻抗的频率特性,简化了测量过程,为三间隙耦合输出电路工程应用提供了有效的实验手段.     

同轴腔高功率多注速调管注-波互作用系统的模拟设计

以同轴腔高功率多注速调管为研究对象,以大信号程序KLY及PIC粒子模拟软件对其多电子注-波互作用系统开展了一维初始设计、二维等效设计及全三维模拟设计.通过采用二次谐波腔技术及参数优化,使同轴腔注-波互作用系统达到了70％以上的计算效率.与传统长漂移管方案注-波互作用系统相比,二次谐波腔方案不仅可以获得较高的注-波互作用效率,并且其系统长度可比传统方案缩短35％,有利于器件小型化.文中给出了以单通道圆柱腔代替多通道同轴腔的注-波互作用系统二维等效快速计算方法,与一维及三维计算结果的对比表明,这种方法具有较高的计算精度.     

Effects of slots/holes in disks on frequencies of TM01 and EH11 waves in disk-loaded waveguides

It has been proven that the combination of boring four holes in each disk at certain radial positions R_c and properly reducing the cavity diameter 2b can make the frequency of the $\text{2π}\text{3}$ mode for TM₀₁ waves invariable and the frequency band for EH₁₁ waves rising with respect to the case without holes in the disks. Taking the SLAC no. 4 cavity as an example, when R_c = 28 mm and the hole diameter 2h = 9 or 11 mm as well as d(2b) = ?0.12 or ?0.28 mm, the operating frequency ($\text{2π}\text{3}$ mode and TM₀₁ wave) remains at 2856 MHz but the EH₁₁ wave frequency band will move up to about 5.5 or 11 MHz with respect to the case without holes in the disks respectively. Obviously, this technique, for example, could be used in Nos. 3, 4 and 5 cavities of the SLAC constant gradient structures for substantially increasing the BBU threshold current of the high energy electron linac using SLAC sections as the accelerating tubes.     

TE013 Mode High Temperature Superconductor Millimeter Resonator

This paper describes a TE₀₁₃ mode dielectric resonator at 36.098 GHz. The dielectric resonator was formed by sandwiching a cylindrical piece of polished dielectric (sapphire) rod between two GdBa₂Cu₃O_7–x (GBCO) High Temperature Superconductor (HTS) thin films. The resonator was tested as a two-port device at a temperature of 77 K. A 62700 unload quality factor Q ₀ was obtained. The surface resistance (Rs) of the HTS film had been determined as 9.4 m at 77 K and 36 GHz.     

Measurement of the moisture content with a cylindrical resonatingcavity in TM010 mode

A new resonating mode has been used in a cylindrical cavity to measure the moisture content and the specific mass of cigarettes. A simple theoretic calculation gives the relation between the sample complex permittivity and the characteristics of the cavity. A model is proposed to extract the moisture content and the specific mass from the complex permittivity. An experimental setup has been demonstrated. It uses a servo-controlled oscillator. This setup is ready to be tried on a production machine     

PPLN谐振倍频外腔输出模场的模拟研究

为了探究PPLN外部谐振倍频腔的输出模式,从菲涅尔-基尔霍夫衍射积分公式出发,采用快速傅里叶变换法(FFT)和Fox-Li迭代法数值模拟高斯反射率圆形平凹倍频腔输出基模的场强分布、相位分布和光束质量M2因子,同时与圆形双凹倍频腔做了比较.计算结果表明,两类倍频谐振腔输出塞模均为高斯分布,腔长变化对两类倍频腔输出光束质量...     

Zn-Doping Dependence of Stripe Order in La1.905Ba0.095CuO4

The effect of Zn-doping on the stripe order in La_1.905Ba_0.095CuO₄ has been studied by means of x-ray and neutron diffraction as well as magnetization measurements. While 1% Zn leads to an increase of the spin stripe order, it unexpectedly causes a wipe out of the visibility of the charge stripe order. A magnetic field of 10 Tesla applied along the c-axis has no reversing effect on the charge order. We compare this observation with the Zn-doping dependence of the crystal structure, superconductivity, and normal state magnetism.     

High temperature thermal stability of CsAlSiO4 and CsAlSi2O6

One CsAlSiO₄ and three nonstoichiometric CsAlSi₂O₆ phases have been studied by TGA. Weight losses (due primarily to cesium volatilization) varied substantially but were all rather low for cesium compounds.     

High pressure synthesis of Gd3InO6, Tb3InO6 and Lu3InO6

Three new compounds, X₃InO₆ (X = Gd, Tb, Lu) were prepared at 1–4 GPa, ～1050°C. They are monoclinic, space group $\text{P}\text{2}{}_1\text{n}$ with $\text{a}\text{? 8.9}\text{A}\text{?}$, $\text{b}\text{? 9.8}\text{A}\text{?}$, $\text{c}\text{? 5.9}\text{A}\text{?}$, β ～ 95° and Z = 4.